The elder Miller spoke with The Mirror and admitted her younger sibling may be wearing someone else's design for her special day.

"There will be a lot of competition from the likes of Galliano and other designers, so I doubt I'll be making her dress," she told the news outlet.

Sienna and Jude have had an on-again, off-again relationship for some time now. The duo broke up in 2005 after Law admitted he cheated on the actress with his children's nanny, but the pair reconciled last year.

While Savannah was reportedly less-than-thrilled about the twosome rekindling their romance, it looks as though she's finally at peace with it.

"We spent two weeks in Puglia in southern Italy and swam, cooked and chilled out together," she told the news source.

If you had a fashion designer sibling, would you wear his or her design, no matter what? Or would you shop around like most brides do?